1. Field of the Invention
The present invention relates to a high-capacity Positive Temperature Coefficient (PTC) heater. More particularly, the present invention relates to a high-capacity PTC heater, in which heat-radiating fins are attached to either side of PTC rods by bonding to further improve heat transfer efficiency from the PTC rods to the heat-radiating fins, the heat-radiating fins bonded to the heat-radiating fins exclude a fixing device for fixing the heat-radiating fins in position to facilitate assembly and fabrication, the heat-radiating fins are formed as louver fins to increase a heat exchange area with the air, thereby improving overall heat exchange efficiency, and the thickness of the PTC rods is reduced and the width of the PTC rods and of the heat-radiating fins is increased to improve heat transfer and exchange efficiency, so that high-capacity output can be obtained.
2. Description of Related Art
A vehicle is equipped with an air conditioning system for selectively supplying cold and warm air to the inside thereof. In the summer season, an air conditioner is actuated to supply the cold air. In the winter season, a heater is actuated to supply the warm air.
In general, the heater is based on a heating system in which coolant heated by circulation through an engine exchanges heat with the air introduced by a fan, so that warmed air is supplied to the inside of the vehicle. This heating system has high energy efficiency because it uses the heat generated from the engine.
However, in the winter season, heating is not performed immediately after the engine is started since it takes some time until the engine is heated after being started. As such, the engine often idles for a predetermined time prior to moving the vehicle until the coolant is heated to a temperature suitable for the heating. This idling of the engine causes energy waste and environmental pollution.
In order to prevent this problem, there has been used a method of heating the interior of the vehicle using a separate pre-heater for a predetermined time when the engine is being warmed up. A conventional heater using a heating coil effectively performs the heating due to high heat generation, but has problems such as high fire danger and frequent repair and replacement of parts due to short lifetime of the heating coil.
Thus, a heater using a Positive Temperature Coefficient (PTC) element has recently been developed. This PTC heater has low fire danger, and can guarantee semi-permanent use due to long lifetime. For this reason, the coverage of the PTC heater becomes very wide. Further, the PTC heater used for a pre-heater generally has a relatively small capacity in view of its characteristics. Recently, there has been a tendency to develop a high-capacity PTC heater due to diversification of vehicles and user demand.
FIGS. 1 and 2 are schematic exploded perspective views illustrating the structure of a conventional PTC heater.
Referring to FIGS. 1 and 2, the conventional PTC heater includes a plurality of PTC rods 10 generating heat when electric power is supplied thereto, each of the PTC rods 10 having a built-in PTC element and an anode terminal 11 protruding from one end thereof; heat-radiating fin modules 20, which are in close contact with opposite sides of the respective PTC rods 10; cathode terminals 30 disposed in parallel between the neighboring heat-radiating fin modules 20; and upper and lower housings 40 and 50 coupled to opposite longitudinal ends of the PTC rods 10.
At this time, side frames 60 are mounted on left-hand and right-hand outer sides of the outermost heat-radiating fin modules 20 such that the PTC rods 10, heat-radiating fin modules 20 and cathode terminals 30, all of which are disposed parallel to one another, can be coupled in close contact with each other between the upper and lower housings 40 and 50. In detail, the side frames 60 are curved inwards, and are coupled to the upper and lower housings 40 and 50. The PTC rods 10, heat-radiating fin modules 20 and cathode terminals 30 are coupled in close contact with one another by means of an elastic contact force of the curved side frames 60. As a result, this coupling provides the entire structure of the PTC heater, which allows elasticity and heat to be efficiently transferred among the PTC rods 10, the heat-radiating fin modules 20 and the cathode terminals 30.
Meanwhile, as illustrated in FIG. 1, each heat-radiating fin module 20 is for increasing efficiency with which each PTC rod 10 exchanges heat with the air, and includes a heat-radiating fin 21 corrugated along the length so as to increase a contact area with the air, a case 22 fixedly holding the heat-radiating fin 21, and a cover 23 fastened to the case 22 by bolts 24 so as to close an open side of the case 22. Here, in order to fix the heat-radiating fin 21 as a component for substantially improving the heat-exchange efficiency, the case 22 and the cover 23 are separately prepared such that the heat-radiating fin 21 is not separated or moving from the PTC rod 10.
Thus, each heat-radiating fin module 20 is complicated when manufactured and increases the number of parts since the case 22 and cover 23 are additionally required to fix the heat-radiating fin 21. In order to solve this problem, the method of manufacturing the PTC heater is changed. For example, as illustrated in FIG. 2, a method of manufacturing each heat-radiating fin module 20′ using a simple fin guide 25 and heat-radiating fin 21 has been developed. In this method, the heat-radiating fin module 20′ also requires the fin guide 25 to fix the heat-radiating fin 21, and the fin guide 25 is configured such that opposite longitudinal edges thereof are bent into flanges 25a. Although this structure can be regarded to be simpler than that of FIG. 1, the heat-radiating fin module 20′ still suffers from a complicated manufacturing process and a large number of parts.
Further, since the separate part such as the case 22 or the fin guide 25 is interposed between the heat-radiating fin 21 and the PTC rod 10, heat transfer efficiency from the PTC rod 10 to the heat-radiating fin 21 is lowered. Therefore, this type of heater is not suitable for the high-capacity PTC heater in terms of efficiency.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.